Packaged power accumulator



April 8, 1947.

E. A. ROCKWELL PACKAGED POWER ACCUMULATOR Filed April '7, 1944 2' Sheets-Sheet 1 .2 5m) 5mm,

. f 721/6717527 4 Zaward' Q. Z2061! April 8, 1947. E. A. ROCKWELL 8,

PACKAGED POWER ACCUMULATOR Filed April 7, 1944 2 Sheets-Sheet 2 f'zvenl or Patented Apr. 8, 1947 UNITED STATES PATENT OFFICE PACKAGED POWER ACCUMULATOR Edward A. Rockwell, Cleveland, Ohio, assignor,

by mesne assignments, to Borg-Warner Corporation, Chicago, Ill., a corporation of Illinois Application April 7, 1944, Serial No. 530,079

19 Claims.

maintain hydraulic fluid pressure between se-' lected maximum and minimum levels of pressure and wherein the accumulator, the generator and the other necessary equipment are all nested together in a compact efficient manner and are embraceably supported by one housing so that the unit may be readily located and mounted in the most advantageous position.

'It is an object to provide an improved accumulator arrangement which lends itself particularly to incorporation in a single package assembly.

It is an important object of this invention to provide a pressure accumulator and loW pressure reservoir which may be connected up to a system for pressureutilization of hydraulic fluid, such as a brake system wherein thesystem is adapted to operate as a closed system with all the air excluded from the system. Also, a more particular object is to provide improved means for effectively bleeding the system, wherein a pressure bleeder can be used to force fluid through the lines to exclude air.

' A further important object of the invention is to combine a spring accumulator with an aircharged accumulator so in case of failure of the air pressure or puncturing of the flexible diaphragm in the air-charged accumulator, the spring accumulator Will take over and maintain the system in operation, this being important on brakes so as to increase the safety for brake operation.

Another object is the provision of a unit of the said type incorporating in an improved and novel manner a first primary compact accumulator and a second relatively smaller capacity seconda'ry accumulator of the plunger type particularly effective for operating the electrical control switch for stopping andstarting the driving electric motor in accordance with the level of pressure within the unit.

An additional object is the provision of a special snap action switch and operating connection for actuation by the secondary accumulator.

Still another object is the provision of an atmospheridpressure control accumulator arrangement effective to maintain atmospheric pressure within the fluid in the low pressure intake portion of the accumulator.

A still further detailed object is the formation of the supporting and enclosing housing in a. cylindrical'shape for the ready reception of pis-. ton-like partitions effective to properly divide up the interior of the housing as well as to support the several elements of equipment.

The above and other objects, advantages and uses of. my invention will become apparent from a reading of the following specification takenin connection with the accompanying drawings which form a part thereof and wherein:

Fig. 1 is a schematic layout view indicatin one system arrangement of which my invention j is particularly adapted to form a part;

Fig. 2 is an axial sectional view of my special arrangement of unitary or packaged hydrauLc power generating and accumulating'assembly;

Fig. 3 is a transverse cross-sectional View taken substantially on the line 3-3 of Fig. 2; and

Fig. 4 is an elevational view showing the rear portion of the switch mechanism disclosed in the right-hand portion of Fig. 2.

Referring in greater detail to the figures 0f' the drawings and first to Fig. 1, there is illustrated schematically a typical system arrangement of which my invention is particuiazly adapted to form a component part. Essentially my special arrangement of unitary or packaged hydraulic power generating and accumulating as-..

sembly indicated. generally at A functions to maintain a pressure level between selected maximum and minimum values. As Will appear from the detailed description, this unit A includes an electric driving motor fed by a supply of elece trical current and control therefor designated generally at B. Electrical supply and control B is effective to automatically start and stopthe electric motor driven pressure fluid generator in accordance with the rise and fall of pressure within the accumulator unit A. As an illustration of one use for the hydraulic pressure supply maintained in the accumulator A, there is illus: trated a manually controlled modulating valve assembly C effective to withdraw hydraulic pres,{

sure from the accumulator A thus changing the level thereof, which pressure fluid is delivered to a brake shoe operating motor indicated generally at D.

In the more particular aspects of my invention,

the same is directed to the construction, the arrangement, and to the mode of coaction of the component parts making up accumulator unitA. Accumulator A comprises generally an electric.

motor I driving a hydraulic fluid pressure generator 2, compactly and embraceably. received within toroidal or donut-shaped primary air accumulator 3 and axially spaced from smaller capacity secondary switch-actuating hydraulic accumulator 4 in turn compactly and embraceably received within a second toroidal or donutshaped atmospheric pressure accumulator 5, and

electric motor control snap action .switch' assembly 6 carried in axial alignment with secondary accumulator 4 for actuation thereby, all of the above elements being supportably carried by a unifying housing assembly 7 including a high pressure cylindrical housing portion 1a and a low pressure cylindrical housingiportion b..

Electric motor I is of a readily avai-lable'form including armature Ii] rotatable within field winding II supported by motor housingI2-which terminates in radial flange I3. The driving end of motor armature IIi has a coupling assembly I irotatably supported in an anti-friction bearing. Pressure. fluid. generator 2 comprises a pair of meshing gears" I6ii and I1; rotatably received.

within aapair of overlapping cylindricalchambersi I'B and I9, these gears meshing in the area of" overlapping of the chambers. Low: pressure fluid from the lowpressure end of the accumulator isintroduced ordrawn into the generator proper through passage ZI carried around the periphery of'the' gears and" discharged through passage 22. Passage'23 permits the recirculation of liquid at low pressure from discharge-passage 22 back around to inlet passage 2! during the initial'starting of the electric motor I thus eliminating startingthemotorunder load. The initial delivery of fl'ui'd by thegears to passages 22 and 23 places the same in contact with pistonlike valve 24 receivable in a complementary shaped cylinder-like port 25' communicating with outlet-passage26-leadingto check valve 2? discharging into thesurrounding accumulator 3. A small tolerance is allowed between piston-like valve 24 and port 25 to-cause alimited-flow therebetween in the-direction of outlet passage 25 with the-result that piston-like valve 24 begins to move freely inresponse to the-generated pressure acting'thereon, this action being insured by Venturi-like restriction28 in passage 23 causing the pressure to buildup as the electric motor I6 gains speed. The operation of piston-like valve 24 raises cylindrical stem 29' shifting'reducedstem portion 3-l transversely of the lower leg portion of passage 23 and" moving piston-like portion 32 across the passage 23 shutting'off the flow therethrough and loading the gears to produce. full output through passage 25 and check'valve 21. The under side of'piston 321s placedin communication with lowpressure inlet 2I through pas.- sage' 33; 7

It .will'thus appear that uponthe electric motor IIliflrst being started the same operates under appreciably no load since the fluid pressure generator 2 ismerely recirculating the output fluid. back around through. bypassv passage 23. tothe. inlet of 'thegenerator.

The generator housing: proper is preferablyformed; in two. transversely divided parts as and 36 held together by cap screws 31. The outer. section 34 isshoWn as including an integral onepiece radial flange 38 adapted to function as one end closure for the accumulator 3, and also supportradial flange I3 oi the electricmotor housing, flange I 3 beingiastened to flange or closure member 38 by means of capscrews 39. Flange or. closure member 38 is formed with. a generally axialorifice 4| in alignment with upper gear l6 of generator 2 and arranged to support a coupling assembly 42 for drivingly coupling electric motor l9 and upper gear I8. Closure flange 38 is formed about its periphery with an annular channel 38a for reception of a flexible seal ring functioning to provide a seal with housing portion'la. Snap ring 381) is partially received in a complementary annular recess in housing portion Ia and functions to retain closure flange 38 in place. This coupling assembly 42 comprises essentially a bushing insert 43 confined in position by a snap ring 44 and provided with flexible sealing rings as indicated. A rotatable bushing 46 has a radial flange 41 engaging a bearing washer 48 in turn compressing a flexible seal ring as indicated. Rotatable bushing t5 is internally splined for cooperation with a complementary splined terminal portion of upper gear I6 and receives in the outer terminal, the non-circular end of fa-second splined gear 52'being fastened thereto by means'of. a diametrically extending pin 5i.

Splined gear 52 is received within complementarily splined motor coup-ling assembly I4. Ball check valve 53 places the axial passages through the. gears and the sealed coupling assembly in communication with the low pressure portion of the accumulator with but a slight or few pounds of drop in pressure across the ball check valve 53.

The right-half 36 of the generator housing proper includes a radial flange portion 54 formed in theperiphery thereof with a recessed annular channel 55 for thereception of a sealing ring to provide a seal with the accumulator partition as will appear; .A passage 56' places the accumulator 3 in communication with, the auxiliary, hydraulic accumulator 4.

Still another pas-sage 51 through flange 5.4 is.

threaded to receive and support checkvalve58 serving the very important function'of facilitating the air bleeding of the generator and'accumulator unit. Check valve 58 and outlet check valve 21 ar of similar construction and hence only valve 58 will'bedescribed in'its essentialdetails. ,Air'

'b-leed check: valve 58 comprises essentially a threaded base portion for reception within the threaded terminal of passage 51; an outwardlyextending tubular body portion receiving a valve proper 59 perforated at 60 to allow the passage offluid-therepast when'open, this valve 59 being normally urged toward closed position by compression springs confined within. the valvebody:

by a threaded closure 6 I Toroidal or donut-shapedprimary accumulator of. the housing and; presents. a; radial flange. within flexible tube 62 for; clamping the tube.

against a flange insert member. 66 andthe. housring wall by means of nut 61, allvery much in a manner similar to that in which an-automobileinner tube is arranged. The difference resides: principally in that the flexible tube '62 is generally flat. in cross-section having a pairof. opposed walls extendingvgenerally parallel to the. major.-

axis, as well. as having the air inlet valvemem'ber extending radial'y outwardly through the housing instead of radially inwardly as in the case of an autornbil inner tube; A radially inwardly spacedcircular cage 68 is formed with a plurality of radial perforations 69, this cage functioningto admitpressure fluid into c'ohtactwi th the flexible would otherwise shut ofi the exit of high pressure fluid from discharge port 12.

On the opposite side of flexible tube 62 from outlet port 12 there is located a partition ring l3 having n inner circular opening l4 complementary in size to pump flange 54, a sealing ring iscarried within annular groove 55 of the pump flange serving to provide a seal. Partition ring 13 has a circular outer periphery formed with an annular groove 15 for the reception of a flexible sealing ring cooperating with the inner periphery of tubularhousing wall 'ib to provide a seal thereloetween. Shoulder 16 on the partition ring 13 supports one terminal ofcage 68 against radial inward movement. Recessed annu ar channel I! receives the outer periphery of a filter screen 18 confinedtherein by a snap ring 79. Snap ring 89 is received in a similar recessed annular channel in the inner periphery of housing portion 1b and functions to hold partition ring 73 against axial movement when subject to the pressure within primary accumulator 3.

Secondary switch-actuating accumulator 4 comprises a fixed tubular piston 8i threadably attached to pump housing section 35 at one end thereof forcommunication with primary accumulator 3 through passage 58. Cylinder 82 tele-.- scopically embraces p ston 8! in sealed relation thereto and is normal'y urged in telescoping direction by an embracing low rate compression spring 83 acting against radial flange 84. Fixed piston 85 is provided about the periphery thereof with rel eving grooves 85 and is given a lapped fit within telescoping cylinder 82. Radial flange guide extension 89 for cooperation with control switch 6 in a special manner to be described.

It will thus appear that in operationisecondary relatively small capacity accumulator 4 receives pressure from primary accumulator 3 through passage 56 causing reciprocable cylinder 82 to move in extended direction against the action of low rate compression spring 83 to an extent determined by the value of the pressure that has been built up by pressure generator 2. By correlating the movement of cylinder 82 with the action of control switch 6, as will appear, a more effective and eflicient operation of electric motor 1 and pressure generator 2 is accomplished.

Atmospheric pressure accumulator 5 comprises a second larger toroidal or donut-shaped flexible tube 90 received within housing portion. lb axially spaced from donut tube 52 of primary accumulator 3 on' the opposite side of partition wall 13 and. spaced radially in embracing relation to secondary switch-actuating accumulator 4. *Alimasthead vent assembly'" 9| function's to "admit atmospheric pressure to the interior of flexible tube at all times. This vent assembly BI is similar in construction to valve assembly 63 of primary accumulator 3 above described, except that a vent valve 921s employed instead of a connection for the introduction of super-atmospheric pressure as in the case of the former valve assembly. A tubular cage 93 is interposed between flexible tube 98 and secondary accumulator 4 to limit the radial inward movement of tube 90, this tube being preferably supported at one terminal on generator housing section 36 and at the other terminal on'the housing closure as will appear.

Perforation 9 3 allows the free flow of low pressurefluid about secondary accumulator 4 and It will be noted that atmospheric pressure accumulator tube 90 is considercross-section than primaryably larger in accumulator tube 62 for a reason that Will appear. Atmospheric pressure accumulator tube 90 is always subject to atmospheric pressure on the primary accumulator tube 62 since it must per;

form its function in response to atmospheric pressure which is relatively low.

Accumulator-actuated motor control switch assembly-fi comprises adjusting wrench or plunger 9?, having a non-circular terminal portion 91afunctioning as a wrench to adjust internally threaded closure cap HM, which in turn is engageable by cup 89 of cylinder 82. transversely extending switch-actuating pin 99 effective to cause the snap operation of switch assembly proper set upon movement past the over center position. Sleeve 93 has radially extending lingers Ill! slidably cooperating with guide 552 that may be formed either in the housing end closure or in a separate part attached thereto. Compression spring H33 urges sleeve 98 in the direction of reciprocable cylinder 82 of secondary accumulator 4. Closure cap I04 is orificed for cooperation with adjusting wrench 9'5 and is internally threaded for attachment to the termi nal threaded portion of sleeve 98. This arrangement provides for external adjustment ofthe cut out pressure as well as the cut in pressure.

A radial flange W5 is carried-on the outside portion of plungerlll and is held in engagement with the outsideterminal of sleeve 98 by means of a second'internally threaded centrall oriflced cap vides for manual override operation of the switch when desired, merely by manually engaging terminal bonnet l d6. Q

The switch assembly proper Hill includes a snap action mechanism comprising a walking beam iill drivingly connected to a switch-operating shaft H38 contacted by a roller Hi9 carried on the end of an over-center swinging arm or yoke Hi This arm or yoke member embraces an arcuate protuberance ill carried by switch housing 6a,

this yoke member being urged away from protuberance ill by compressionspring H2 with the result that the movement of actuating pin 89 by plunger 9? and sleeve 58 past its center position with reference to the axis of supporting shaft !68 is efiective to cause a snap action or 1 quick arcuate movement of walking beam Inland Sleeve 98 carries It will be seen that this arrangement pro same; is ,moved-, there is provided opposite each te minal of the Walking beam duplicate latches M5,; Each latch is supported on a pivot H4 and is urged-in the direction of the walking beam III'I bycompression spring I I5. Shoulders IIB function to lock the associated terminal of Walking beam IIl'I subjectto the subsequent release there- Q-fgby inwardly extendingfinger III being contasted byarcua-tely shiftable arm or yoke IIII. Oseillatable shaft I as also supports in spaced relation'to walking beam IIlI another arcuately swingable arm H9 supported thereon in driving relation-. Arm II9 carries contacts I cushioned by compression springs I2I (only one being shown), The arm IE9 is swung arcuately to bring contact-I29 intoengagement with grounded contact 122.carried by housing 6a or into engage ment-with stop I23.

Supporting and enclosing housing assembly I comprises inaddition to portion Ia and lb already described a low pressure chamber closure member IZGhaving a circular periphery formed with a recessed annular channel I2'I for reception ofa.flexible seal ring providing a seal with the embracing housing portion 'Ib, this closure memher, being confined in-position by a snap ring I28 fittingin a complementary channel on the inner periphery of the housing lb. This closure memberis-forn ed with an inlet port I29 for the return introduction of low pressure fluid. A stud bolt I 3;}, or as many thereof as is desired, ma be threadably mountedin end closure I26 for" attachmentto a suitable support such, for example, as, a, bracket. I'i, a similar supporting arrange- I ment being also provided for the opposite end closure I38. Air bleed assembly I37 serves to bleed air from the low pressure accumulator portion 4. A reflllplug assembly I38 provides for readily replenishing hydraulic fluid.

Referringagain to Fig. 1 in somewhat'greater detail, the driving power supply assembly B comprises a storage battery arranged to deliver electricalcurrent through contacts Md of relay hi2 when closed, to electrical motor I. Relay M2 is normally energized and deenergized automatically'by the operation of control switch 6 in response to the'rise and fall of pressure in the accumulator-A. Contro1 current passes from the battery through contact I22 of switch 6. In the event that the pressure in the accumulator has dropped to a point permitting cylinder 82 to move in the telescoping direction sufiiciently to allow spring I03 to shift plunger 9'! and sleeve 98 and thus effect the snap action of walking beam IE7 and switch arm M8 to contact ground terminal I22, then relay M2 will be energized to close contacts I420 and deliver current to the electric motor I for operating the same to drive fluid pressure generator 2. In addition, signal light I39 will beilluminated to indicate the operating condit on iele tri mo Electric motor; I will continue to operate until the, hydraulic pressureacting on shiftable cylinder 82, rises to a sufficient level to cause the cylinder to; again contact plunger 91 and shift the samesufliciently to cause snap action of walking beam I61 and the moving of arm I I9 to separate live contact I 20 from ground contact I22 thus opening the motor circuit. Lowering of the pressurqmayagain be brought about by operation otmanuallycontrolled modulator valve C to deliver pressure fluid to the brake motor assembly and the consequent operation of switch 6 tov ar e. e t ie et ard. fluid ressure sn:

orator 2.

As a a stand-by means-for manually energizingrelay I42 a manual pus h button controlled circuit maybe provided as shown.

From the above, it will be seen that I have, provided an improved and important relationship of elements resultingin compactness and. effi ciency in'accumulators generally. For example, primary high'pressure toroidal tube 62 may be v readily'substituted for the-present inefficient, cumbersome diaphragm now incorporated in the well-known spherical form; of accumulator. The,

equivalent of tubular surrounding hOLlSiIlg portion 'la and associated piston-like end closure members may also be employed and this arrange ment may be used-eitherwith or without the incorporation of a pressure fluid generatorwithh in the housing.

It will appear further that, when the probleni is merely one of maintaining atmospheric pres-,.

sure within a supply of hydraulic fluid, then an, arrangement equivalent of that shown 111 00111, nection with low pressure toroidal tube may be employed for this purpose.

While I have disclosed my invention in c0n-, nection with certain specific embodiments thereof, it isto be understood that this is byway of example only and that equivalent arrangements are contemplated as coming within my invention said tubular wall for introducing super-atmose. pheric pressure into said tube, means forintro-,.

duclng hydraulic fluid under super-atmospheric pressure into contact with the outer periphery of said toroidal tube Within said housing, and a cylindrical perforate wall extending axially through said toroidal tube for limiting radially inward flexing of the tube.

2. In a hydraulic pressure fluid accumulator, means defining a generally elongated housing. having a tubular surrounding wall, means define ing piston-like end closure members for said tubular wall, means definin a toroidal shaped flex-, ible tube received within said housing adjacent th inner periphery of said tubular wall, valve means extending through said tubular wall ofv said housing for introducing super-atmospheric. pressure into said toroidal tube, means defining a perforatedgenerally circular Wall disposed contoroidal shaped flexible housing, atmospheric air vent means extending through the wall of said housing for exposing the tube received within said interior of said tube to atmospheric pressure,

. means defining an inlet port for the introduction of low pressure return hydraulic fluid into said housing into contact with the exterior surface of said tube, whereby to prevent occlusion of air inthe low pressure hydraulic fluid; and a perforate tubular wall arranged concentrically within said toroidal tube for limiting radially inward flexing of said tube.

4. In a hydraulic pressure fluid accumulator, means defining a housing having a surrounding wall generally circular in transverse cross section, an endless toroidal shaped flexible tube received Within said housing with the radial outer periphery thereof adjacent the inner surface of ""having a surrounding tubular wall portion, pis- "tQl'l-llke end'closure members received in sealed *re lationto said tubular wall, an endless toroidal E"sh'apedflexibletubereceived within said housing,

yalve' means-extending through the wall of said h ousingfor introducing super-atmospheric pres- "sure" into said tube; pressure fluid generating means supported between said piston-like end j closure members in axially arranged position with 'r'espect"to"said toroidal tube and embraced by said tube, means defining an inlet to said generator for introducing low pressure fluid thereto, and means defining a one-way check valve for discharging pressure fluid into contact with the external surface of said tube, said pressure fluid having a higher value than the super-atmospheric pressure in said tube.

6. In a hydraulic pressure fluid accumulator, walls defining a housing; a flexible endless tube received within said housing, said tube having a continuous external annular surface and a closed internal annular surface; valve means extending into said housing for introducing superatmospheric pressure into contact with the internal annular surface of said tube; and means for introducing hydraulic fluid into said housing under super-atmospheric pressure into contact with the external annular surface of said tube.

7. The hydraulic pressure fluid accumulator defined in claim 6 in combination with a perforate supporting structure within the housing for limiting expansion of the tube in a radially inward direction, the housing being arranged to limit flexing of the tube in a radially outward direction.

8. In a hydraulic pressure fluid accumulator, walls defining a housing of generally tubular shape; an endless ring shaped tube received within said housing, said tube having a continuous flexible wall adapted to be alfected by internal and external pressures; valve means extending into said housing for introducing super-atmospheric pressure into contact with the internal surface of said tube; means for introducing hydraulic fluid pressure into said housing to be effective upon the exterior surface of said tube;

7 and a perforate wall within said housing arranged to' limit the radially inward flexing of said tube.

9. The hydraulic pressure fluid accumulator defined in claim 8 in combination with a. hydraulic pressure fluid generator arranged approximately axially within said tube and communicating with the means for introducing hydraulic pressure fluid into the housing. 10

10. In a hydraulic pressure fluid accumulator, means defining a housing having a surrounding wall; a flexiblebagin, said housing, said bag comprising an endless ring shaped tube having a continuousflexible wall; means for admitting a'ir'at atmospheric pressure to the interior of said bag; and means adapted to admit return hydraulic pressure fluid into said housing exteriorto said bag to be effective upon the exterior surface of said bag whereby to prevent occlusion of air' in said hydraulic. pressure liquid. '11. A hydraulicpressure fluid accumulatoras deflnedinclaim 10 wherein means are provided which extend axially through the bag for lirniting radially inward flexing of the adjacent wall of 'sai'dbag. a l

12. In a hydraulic pressure fluid accumulator, housing walls defining a high pressure delivery chamber; pressure "generating means in said chamber for delivering pressure liquid thereto; a toroidal flexible "body of hollow cross section encompassing lsaid .pressure generating means, said body. beirig internally charged with superatmospheric pressure and being externally T'affected by pressure liquid fromsaid generating means; and a perforatesupporting' structure in said chamber between said generating means and said toroidal b-odyand arranged to limit radially inward flexingofsaid toroidal body, the radially outward flexing of said toroidal body beinglim- 13. In a hydraulic pressure fluid accumulator, housing walls defining a high pressure liquid delivery chamber and a low pressure return liquid chamber arranged in side-by-side relationship; perforate annular supporting structures in said chambers; toroidal flexible bodies of hollow cross section in said chambers between the respective supporting structures and the housing walls, the toroidal body in said low pressure chamber being vented to atmospheric pressure and the toroidal body in said high pressure chamber being charged with super-atmospheric pressure; pressure generating means for delivering pressure liquid into said high pressure chamber to be effective upon the flexible toroidal body therein, said pressure generating means being arranged axially within and encompassed by the flexible toroidal body in said high pressure chamber; and means defining an inlet port for introducing low pressure return liquid into said low pressure chamber to be effective upon the flexible toroidal body therein; the radially outward flexing of said toroidal bodies being limited by said housing wall, and the radially inward flexing of said toroidal bodies being limited by the respective perforate supporting structures.

14. In a hydraulic pressure fluid accumulator, means defining a housing having a tubular surrounding wall; a transverse Wall dividing the interior of said housing into a first high pressure chamber and a second low pressure fluid return chamber; a perforate cylinder within said high pressure chamber and arranged coaxial to said tubular housing wall; an annulus shaped flexible tube received within said high pressure chamber "betweensaid perforate supporting structure and the housing'wall, radially inward and outward movement of said annulus tube being 'limited respectively by said perforate cylinder and said "housing wall; valve means extending through said tubular housing wall for introducing superatmospheric pressure into said annulus tube; means for introducing hydraulic fluid into said high pressure chamber under super-atmospheric pressure to contact with the exterior surface of said annulus tube; a perforate cylinder within said low pressure return chamber arranged coaxial 'to said tubular housing wall; a second annulus "shaped flexible tube received within said low pressure'return chamber between said housing wall and the adjacent perforate cylinder, radially "inward and'outward flexing of said second'annulus tube 'being'limited respectively by said lastmentioned perforate cylinder and said housing wall; venting means for constantly maintaining it said second annulus tube in communication with surrounding atmospheric pressure; "means for introducing low pressure return fluid "into said second 'low pressure fluid return chamand inlet her to be effective upon the annulus shaped flexible tube therein.

15..A hydraulic pressure fluid accumulator "arangement as defined in claim 14 which includes means defining a fluid pressure generator ar-- ranged axially within and encompassed by said first annulus shaped flexible tube for introducing "hydraulic pressure fluid into said first high pressure chamber.

16."In a hydraulic pressure generator and accumulating assembly, the improvements which comprise a hollow body of toroidal shape, said body being entirely closed except for relatively "s'malllporti means for communicating with the interiorthereof to supplyair thereinto, said body "being "so constructed and arranged" that it is adapted to embrace portions of said'assembly and 'to r'eactin all directions upon hydraulic pressure pressures.

on the exterior thereof. 7

17. Ina hydraulic pressure generatonandaccumulatin'g assembly; as defined in claim" "16,

wherein the Walls'of the body are 'fl'exiblewhereby g.

tobe readily affected by internal' and'external 18. In a'hydrauliopressure generator'andaccumulating assembly, as defined in claim 16, wherein the hollow toroidal bodyis approximately wholly'submerged in the hydraulic pressureffiuid.

19. In'a hydraulic pressure generatoraridac- 'cumulator' assembly, the improvements which comprise a hollow toroidal body wholly submerged in the hydraulic pressure fluid and communicatmg with the atmosphere; said body beirig'adapted to embrace portionsof saidas'sembly'and toreact in all directions upon ambient pressure.

'EDWARD"A. ROCKWELL.

" REFERENCES CITED 7 The following references are of record in-the file of this patent:

UNITED STATES PATENTS 

